Neurochemical properties of the synapses between the parabrachial nucleus-derived CGRP-positive axonal terminals and the GABAergic neurons in the lateral capsular division of central nucleus of amygdala
Neurochemical properties of the synapses between the parabrachial nucleus-derived CGRP-positive axonal terminals and the GABAergic neurons in the lateral capsular division of central nucleus of amygdala
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臂旁核衍生的 CGRP 阳性轴突末端与杏仁核中央核外侧囊区 GABA 能神经元之间突触的神经化学特性
DOI：
10.1007/s12035-014-8713-x
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发表时间：
2015-02-01
影响因子：
5.1
通讯作者：
Dong, Yu-Lin
中科院分区：
文献类型：
--
作者：
Lu, Ya-Cheng;Chen, Yan-Zhou;Dong, Yu-Lin
杏仁核中央核（CeC）外侧囊分裂包含以γ -氨基丁酸（GABA）为主要神经递质的神经元，并表达丰富的降钙素基因相关肽（CGRP）阳性终端。然而，他们之间的关系还没有被披露。采用gad67 -绿色荧光蛋白（GFP）敲入小鼠，采用CGRP1受体mRNA荧光原位杂交与GFP和CGRP免疫荧光组化相结合的方法，研究了CeC内CGRP阳性末端与gaba能神经元之间突触的神经化学特征以及CGRP1受体的潜在参与。用预包埋电镜观察GFP和CGRP突触的超微结构。我们发现CeC中部分gaba能神经元接受臂旁核（PBN）衍生的CGRP神经支配，其中部分gaba能神经元可被皮下注射福尔马林激活。此外，超过90%的由cgrp阳性终端支配的gabaergy神经元也表达CGRP1受体mRNA。cgrp阳性纤维在gaba能体上形成对称突触，在GABA-LI树突轴和棘上形成不对称突触。本研究为CeC内cgrp阳性末端与gaba能神经元之间的突触接触提供了直接的超微结构证据，这可能是PBN到CeC的疼痛相关神经通路的基础，并参与了慢性疼痛的调节。
The lateral capsular division of central nucleus of amygdala (CeC) contains neurons using gamma-amino butyric acid (GABA) as the predominant neurotransmitter and expresses abundant calcitonin gene-related peptide (CGRP)-positive terminals. However, the relationship between them has not been revealed yet. Using GAD67-green fluorescent protein (GFP) knock-in mouse, we investigated the neurochemical features of synapses between CGRP-positive terminals and GABAergic neurons within CeC and the potential involvement of CGRP1 receptor by combining fluorescent in situ hybridization for CGRP1 receptor mRNA with immunofluorescent histochemistry for GFP and CGRP. The ultrastructures of these synapses were investigated with pre-embedding electron microscopy for GFP and CGRP. We found that some GABAergic neurons in the CeC received parabrachial nucleus (PBN) derived CGRP innervations and some of these GABAergic neurons can be activated by subcutaneous injection of formalin. Moreover, more than 90 % GABAergic neurons innervated by CGRP-positive terminal also express CGRP1 receptor mRNA. The CGRP-positive fibers made symmetric synapses onto the GABAergic somata, and asymmetric synapses onto the GABA-LI dendritic shafts and spines. This study provides direct ultrastructural evidences for the synaptic contacts between CGRP-positive terminals and GABAergic neurons within the CeC, which may underlie the pain-related neural pathway from PBN to CeC and be involved in the chronic pain modulation.